The Moon's cycle of phases is one of the most familiar natural phenomena, yet also one of the most misunderstood. This probably comes as no surprise, but research has found that a significant segment of the population, including both elementary students and teachers, mistakenly believes that the Moon's phases are caused by the shadow of the Earth. (In reality, the Earth's shadow only falls upon the Moon once or twice per year during a lunar eclipse.) The authors found, when evaluating 79 children's books that focused on the Moon as a topic or used the Moon prominently in illustrations; the results revealed that many books reinforce misconceptions about lunar phases and even misrepresent the Moon. The authors undertook this study and article to make teachers, parents, and library media specialists aware of potential problems. They discuss specific examples of children's literature and what do about this problem with some specific tips for the classroom.